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I just got my heads back from the machine shop and they plugged the steam holes.
i can say the heads were a 1.94 when i turned them in, he said the wouldnt clean up so he went to 202 and milled / shaved 80 thousandths off them...
What is the purpose of plugging the steam holes ?
The holes are in the head at an angle.If you cut the heads very much they end up inside the head gasket fire ring.I assume you are talking about the sparkplug coolant holes.The 487X heads shouldn't have steam holes in them.
Actually I have had old 487Xs with "400" steam holes. Just sayin! proceed!
i might be calling them wrong, but they are about a lil smaller than a pencil is round and there was 2 i think per cylinder.
parrot69777
I maybe wrong on this,,but i think they were close to the edge of the head, dont quote me on this cause he already put the heads on the block when i got it back from the shop.
2 holes smaller than a pencil with like a lil valley in between them.
Those are sparkplug cooling holes and they were plugged because the head was cut so much
Ok, if they were spark plug holes, what prupose does it serve to plug them up since he shaved my heads so much ?
Go back to post #2.Your question was answered before you asked it.
So should a small hole be drilled in the plugs to allow coolant flow??
No,not all heads have spark plug coolant holes.Coolant will still be on each side of the plugs.
You are looking at an over the road engine that must operate at all temps, altitudes, with questionable maintenance, and conditions and trying to reason the design on a racing engine. You do not need the cooling holes on a racing engine. This it the same reason on a good build you plug the 1 inch deck holes on the block and re drill them, on a racing engine it is a bad design.Quote:
Originally Posted by DaveBauerSS6
On stock steel headed engines I block off the spark plug cooling holes on cylinders 1,7,2,8 and on cyls 3,4,5,6; I open them up on the head to provide additional coolant to the two center cylinders. Any SBC can benefit from this.
If rules allow I also drill and tap center coolant line -6 ( in heads ) to run forward to the side exits of the water pump. You will find that the extra coolant will allow you to run more timing on these cylinders resulting in the ability to make more HP with the 4 center cylinders.
If you decide to plumb this system make sure you use steel fittings in Head and WP and Stainless Lines as the high dollar trick $hit will burn up from header heat...trust me dun made that mistake, only once though...
Last time I checked cylinders 1,7,2,8 and on 3,4,5 and 6 would be all 8 cylinders.I have used the rubber pushloc hose on the coolant lines he refered to for years without burning any of them.I also use aluminum Aeroquip fittings without a problem.
I think he means he plugs them on 1,7,2,8 and opens them up on 3,4,5,6